[ios] Use chrome_browser_state_forward.h in /ios/chrome/browser/gcm

Instead of forward declaring ChromeBrowserState in the ios
namespace, use a header. This will allow moving the class
to the global namespace without having to change all the
forward declaration at the same time.

This CL was uploaded by git cl split.

R=jianli@chromium.org

Bug: 1042208
Change-Id: Iacbce9f831abd0f470636ce16fd153e8e669f5c8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2007584
Auto-Submit: Sylvain Defresne <sdefresne@chromium.org>
Reviewed-by: Jian Li <jianli@chromium.org>
Commit-Queue: Sylvain Defresne <sdefresne@chromium.org>
Cr-Commit-Position: refs/heads/master@{#733930}

ios/chrome/browser/gcm/instance_id/ios_chrome_instance_id_profile_service_factory.h

@@ -10,15 +10,12 @@
 #include "base/macros.h"
 #include "base/no_destructor.h"
 #include "components/keyed_service/ios/browser_state_keyed_service_factory.h"
+#include "ios/chrome/browser/browser_state/chrome_browser_state_forward.h"
 
 namespace instance_id {
 class InstanceIDProfileService;
 }
 
-namespace ios {
-class ChromeBrowserState;
-}
-
 // Singleton that owns all InstanceIDProfileService and associates them with
 // ios::ChromeBrowserState.
 class IOSChromeInstanceIDProfileServiceFactory

ios/chrome/browser/gcm/ios_chrome_gcm_profile_service_factory.h

@@ -11,15 +11,12 @@
 #include "base/macros.h"
 #include "base/no_destructor.h"
 #include "components/keyed_service/ios/browser_state_keyed_service_factory.h"
+#include "ios/chrome/browser/browser_state/chrome_browser_state_forward.h"
 
 namespace gcm {
 class GCMProfileService;
 }
 
-namespace ios {
-class ChromeBrowserState;
-}
-
 // Singleton that owns all GCMProfileService and associates them with
 // ios::ChromeBrowserState.
 class IOSChromeGCMProfileServiceFactory